Display screen or portion thereof with a graphical user interface



Display screen or portion thereof with a graphical user interface

Reproduction 3.1 is a front view of a display screen or portion thereof with a graphical user interface.

The outermost broken line showing a display screen or portion thereof, as well as all broken lines therein showing portions of the graphical user interface, are included for the purpose of illustrating portions of the article and form no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with a graphical user interface, as shown and described. 